Another chance
by charisma26
Summary: A war with Gaia is underway but the gang has extra help - Percy's sister, who died in 1773...what? she was resurrected by Gaia who believed the daughter of Poseiodon with the witch ancestory bloodline could help her ruin the world. As they battle the enemy forces, what happens when Nico and her begin to fall for eachother. Nico/OC NicoxOC please R and R!
1. Chapter 1

Disclaimer: Percy Jackson does not belong to me!

A/N – IN THIS FIC NICO WAS 11 IN THE TITANS CURSE WHICH NOW MAKES HIM 14 NOW!

Anyhow, I haven't seen many Nico/OC stories so I decided to put one up! I hope you enjoy.

Nico was tired. Drained of all his energy. He was so close to face planting the ground he was surprised he hadn't already keeled over. Shadow traveling was SO exhausting. Even though he had gotten better at it over the past few years it killed him inside. He stumbled into the camp, practically tripping over his own two feet as he stumbled to his newly built cabin – The Hades cabin. Ever since the war last year he had been treated differently and it made him feel… warmer inside, that he actually had a family that he could turn to.

It was now the middle of June and Percy and Annabeth were expected to arrive soon, any minute now actually but he was far too tired to greet them. He collapsed onto his bed, falling into an easy slumber.

Nico woke up with a grunt, squinting his eyes against the midday sun. Ughhh, he had only fallen asleep for a few hours but it was better than nothing right? He looked around his cabin, looking at the dark black walls and the simple yet sleek design of the room. He loved it, he loved being here – it was his home now even if he was a bit adamant about it at first. He hooked his Stygian Iron sword on his belt chain and exited his cabin, suddenly excited about the appearance of Percy. Percy was like a brother to him, sometimes he would even shadow travel over to Percy's apartment just to watch stupid movies and eat popcorn.

"Hey Nico" A voice greeted from behind him and he whipped around, his shaggy black hair falling over his eyes. There stood a grinning Annabeth and Percy, hand in hand, looking all lovey dovey it make Nico feel a little bit sick.

"Hi guys, you've finally arrived I see" Nico smiled, dodging Percy's arm that shot out to ruffle his hair. He chuckled, shadow travelling behind the pair to give them a fright.

"That's cheating" Percy exclaimed, though a small smile played on his lips.

"Oh hush you, you cheat as well" Annabeth teased, pinching Percy's cheek. They all shared a laugh and Percy spun around, looking around the whole camp, his eyes eagerly roaming the landscape.

"This is gonna be a good year… I can feel it" Percy stated but just as he said that a figure emerged right in front of them, materialising from thin air. Nico recognised him immediately. It was Poseidon, Percy's dad. He was wearing his normal Bermuda shorts and Hawaiian shirt though he wore a grim expression on his face, a complete contrast to his normal bubbly self. Nico had a sinking feeling in the pit of his stomach – something had gone terribly wrong.

"Dad, what are you doing here?" Percy exclaimed, looking shell shocked at the fact his father just turned up out of the blue. Even Annabeth was staring at Poseidon like he had two heads. A few of the campers jumped as he appeared, even staring at him in awe.

"Percy, my son, it's good to see you" He stated, trying to smile but it came out as a grimace, "And Annabeth and Nico" He added, peering down at the three of them.

"You too dad, what's going on though? Is everything alright on Olympus?" Percy asked anxiously and Nico felt his heart clenching… everything HAD to be okay, they had saved the world from Kronos, it was supposed to be over by now.

Poseidon then looked across the camp, sharing a knowing look with Chiron. Seriously, what in Hades name was going on? Nico felt his palms get sweaty just thinking about all the possibilities.

"Annabeth, I need you to iris message Thalia now, she is needed on a quest this instant" Poseidon demanded, his sea green eyes piercing. Annabeth shared a scared look with the two of them before shakily nodding, not even questioning Poseidon's request, and let go of Percy's hand, going off to call Thalia.

"Dad, what's going on?" Percy asked, crossing his arms across his chest. Nico felt a weird sensation in the pit of his stomach then, like the ground was shifting under his feet making his stomach tingle. He wrapped an arm around his torso, the strange feeling not going away. He felt Poseidon's gaze on him and looked up, curious.

"You can feel it can't you?" Poseidon asked, looking incredibly worried, more worried than Nico had seen him in a long time. Yes, he could feel it – whatever IT was.

"Yes" He stated, the feeling suddenly increasing tenfold. It wasn't painful, just slightly annoying and uncomfortable but wasn't the worst thing he had ever experienced. Percy glanced between the two of them, his mouth gaping, eyebrows pinched together.

"Feel what?" He asked gingerly and Poseidon tore his gaze away from Nico and looked down at his son in what Nico recognised as slight horror.

"Magic" He replied simply and at that word the sky seemed to darken and the winds picked up. Percy frowned, like he was processing what his dad said. Nico's legs suddenly felt shaky – Magic? Bad magic? Good magic? What? He didn't know but he defiantly recognised its power. Did that mean it had something to do with the dead because he could feel it? Were people dying? Ghosts being called? It all just confused him more. AT that moment Annabeth returned, her long blonde hair flying about her face with Thalia in tow. Thalia hadn't changed since the last time Nico had seen her… well duh, of course, she was immortal, he thought, cursing himself for his own idiocy.

"Lord Poseidon, what's going on?" Thalia asked, giving Nico and Percy a quick head nod.

"Something bad" He replied gravely, "ever since the war with Kronos we have been trying to eliminate all the enemies but haven't been as successful as we'd first hoped. It has now come to our attention that Atlas has escaped from his position from under the sky" He said and they all sucked in a breath, their thoughts thinking the worst.

"But how… I thought he was trapped there for eternity" Percy stated, a slight hint of anger to his voice.

"Someone took over from him, freed him and now he is planning to raise Gaia" And with that Nico stopped breathing. What? When? Where? How? He gripped his iron sword tighter and glanced around nervously. No. no way. This could NOT be happening.

"Are you serious?" Annabeth exclaimed, terror in her grey eyes.

"I'm afraid so but that's not all" Poseidon said, exhaling loudly, "That magic you're feeling" Turning towards Nico, "It's them raising someone from the dead, someone powerful" And Nico's heart jolted. Of course, he recognised it now; it was a soul being resurrected. And that terrified him.

Silence fell at Poseidon's grave words so he continued to speak.

"It's your sister Percy… he's bringing your sister back to life" And Nico felt his legs turn to jelly. Oh hades… what?

So… I've had this idea in my head for a long time but wasn't sure if it was alright! Do you want me to continue this idea? Reviews appreciated!


	2. Chapter 2

Disclaimer: Percy Jackson does not belong to me

Thank you for the lovely reviews, your thoughts are very much appreciated.

Poseidon's words hung heavily in the air and Nico felt the air being pushed from his lungs. Was he serious? Was Poseidon actually being serious? Percy's sister? What? Nico was confused, well, more than confused. He was baffled.

"W-What?" Percy stuttered, gripping Annabeths hand tighter, his sea green eyes wide and confused.

"It's not what you think" Poseidon started; "I didn't break the oath again, she was born in 1759" And Nico felt his mouth gape open. This… this was unreal. It was impossible. What the hades was happening?

"Dad… what? I don't understand" Percy stated, his eyebrows furrowing. Exactly my words Perce, exactly my words, Nico thought.

"I don't know the full story son, all I know is Gaia is rising and she's bringing back my daughter but I don't know why" He explained and suddenly Poseidon looked ten times older. The only time Nico had seen that was in the last war – could this situation be just as bad?

"Lord Poseidon, what do you need us to do?" Thalia asked, standing up straight and looking ahead determinedly, her crystal blue eyes shining with fierceness.

"Rescue her, rescue my Cassandra before Gaia gets her – she's a powerful weapon and if Gaia gets her claws in her and manages to twist her sense of reality… it would be dangerous. It was just like Kronos with you Percy" Poseidon said, nodding in Percy's direction, "He thought he could use you for his own purposes, but if Gaia gets to her at her weakest point when she's alone and confused and scared…" Poseidon trailed off, looking distressed. Cassandra… Cassandra… Nico said the name in his head a few times – pretty name, he thought before shaking his head to clear his thoughts.

"Okay… we'll accept the quest – where do you need us?" Annabeth asked, giving Percy a reassuring look and a small shoulder nudge before facing Poseidon. Poseidon smiled in thanks.

"If my timing is correct you've only got a few minutes before the ritual begins – now, Gaia will no doubt have monsters in place to capture her and ward off any interferences so you must be careful. That is why I have asked you four – the children of the big three as well as the smartest demigod should be a good combination. Go to an area just outside of Kansas, we can't pin point its exact location because Gaia's power is blocking us but I think Nico can" Poseidon stated, staring down at Nico. He gulped – it was true, he could feel its power radiating from here.

"Yeah, I know where to go, I can feel it" He muttered, suddenly feeling a bit queasy at the pure, concentrated magic that he could sense. It was powerful, no doubt about that.

"Can you shadow travel us over there or will it be too draining?" Annabeth asked worriedly, her grey eyes shining. Nico shook his head, "No I don't think so, I've been practicing and it isn't too far so I should be okay" And everyone nodded.

"Good luck" Poseidon nodded and he put his hand on Percy's shoulder, "Percy…please be careful and…" He trailed off; looking like a kicked puppy "I failed her once – I won't fail her again" And Nico watched as Percy stared into his dad's eyes and nodded shakily.

"Of course dad – I'll do everything I can" Percy vowed and Poseidon gave a lopsided smile.

"Good, that's good – off you go you four, and for Hade's sake, be careful" He warned seriously before materialising away. Nico refocused and saw that the entire camp had stopped in their usual activities and were staring at them with a hint of confusion, fear and admiration which made his stomach churn. He was so focused on the idea of saving this mysterious girl that it finally dawned on him that Gaia was rising – another war was underway. Nico looked around and met Chiron's eyes. The old centaur looked tired and drained but he stood straight (well, as straight as a half horse man could). He nodded at Nico reassuring before turning around and galloping to the big house.

"Come on guys, we better go" Nico stated, facing his friends, "Grab a hold of me and hang on, I don't wanna lose you guys on the ride" And that caused his friends to give a small chuckle. They all reached out and touched him, Annabeth and Thalia took each of his hands and Percy gripped his shoulder tightly. Here goes nothing, was his last thought before he whooshed him and his friends into the darkness.

It didn't take long to travel to Kansas – under twenty seconds. When he stepped out from the darkness and onto the grassy banks of a wood he stumbled, his legs turning to jelly. Luckily Percy caught him under the arms and gently placed him against a tree to steady himself.

"You okay Nico – you're looking awful pale" Annabeth asked a slight hitch to her voice as she came to stand next to him.

"He's death breath of course he's pale" Thalia stated, striding forward briskly even though she looked worried as well, "Here take this" She ordered, shoving a piece of ambrosia at him "We can't have you collapsing on us now can we?" She smiled and Nico smirked, plopping it in his mouth. Immediately the warmth spread through his veins making him perk up.

"Percy – the magic… it's coming from over there" He stated, jutting his head forward, his shaggy black hair falling over his eyes. Percy looked in the direction and a serious expression came over his face.

"Okay, we just have to rescue this girl and get the hades out of there – shouldn't be that hard right?" Percy asked nervously and Nico and the girls raised their eyebrows at him, "Okay scrap that it seems impossible but… we can do it okay? We can't let Gaia get her" And Nico analysed Percy closely. Even though he hadn't met this girl, hadn't bonded with his sister, Nico knew Percy cared about her already – it was all in his eyes.

"We won't kelp head" Thalia promised, already striding forward with her medusa shield held up in defence, "come on guys you heard lord Poseidon, we haven't got long left" so Nico scuttled after her – he wasn't about to leave his friend to wander into the unknown without backup. Percy and Annabeth soon followed – Annabeth holding her knife, Percy was wielding Riptide and Nico had his own stygian iron sword.

It was less than a minutes' walk till they found the clearing, or rather a space which was crowded with monsters from hellhounds, the two sister gorgons, Empousa, harpies, the minotaur (it must have reformed again) and even telekhines. Nico gulped. There were a lot of monsters here, maybe even more than they could handle but when he looked at Percy and saw the desperation on his face, the fierceness of wanting to save his sister he knew he had to – he wouldn't let this girl down.

"What's the plan then?" Nico asked quietly, not wanting to alert the monsters to their location.

"We kill all the monsters and save my sister – simple" Percy stated, his eyes roaming the crowd of monsters that were surrounding a patch of ground.

"Percy we can't just charge in we need a plan" Annabeth whispered back, holding onto his arm as Percy was about to race forward. Good thinking Annabeth, Percy is incredibly reckless, charging in would not do any good, Nico thought.

"Then what do you propose we do then?" Percy asked tightly, gripping Riptide harder.

"I propose we make a plan" Annabeth sniped back, pulling Percy away by the arm, "Nico – you should shadow travel into the clearing, distract them long enough for us to creep up on them from behind and attack, it should give us an advantage" Nico wasn't about to argue with a hot headed, daughter of Athena – things could turn nasty.

"Okay – wish me luck" Nico muttered before mustering all his energy and shadow traveling to the middle of the clearing, right bang smack in monster central. When he materialised the monsters looked at him with something near confusion and Nico smirked, "Long time no see" He said then Percy, Annabeth and Thalia pounced.

Percy swiped with his sword, whipping around like a razor blade killing or maiming everything he could. Annabeth attacked from below, using her cap of invisibility to get close to the monsters and attacking them with her knife. Thalia chose a more discreet way of attack – she shot her arrows from the trees, killing anything that got close to her friends. Whereas Nico… he was more focused on the shaking of the ground and the fact that he could sense more magic than he thought possible. A hand emerged from the ground, followed by another and soon a body was pulled from the earth. A girl about his age with long sleek black hair in an old fashioned dress collapsed onto the ground, gasping for breath. Her eyes shone with tears as she looked around and Nico realised with a shock how green they were, almost an exact replica of Percy's except they had flecks of bright blue in them.

"Nico – we need to leave soon" Percy shouted to him in the middle of killing a hellhound. Nico nodded jittery and raced forward, pulling the girl to her feet and holding her steady so she wouldn't fall over. She stumbled but followed his lead over to a large oak tree.

"Who are you? What is happening?" She asked hysterically and Nico realised how much of an old fashioned accent she had.

"I'll explain later – we have to go" Nico said, waving over to the rest of his friends. If they didn't get out of here now they would either be killed in the process or overwhelmed by the sheer amount of monsters attacking them.

His friends ran over, breathing heavily and looking exhausted and a little bit bloody. He pulled the girl into his side to stop her from escaping as she was struggling and held out his hand for Thalia to grab a hold of. Once each of his friends were touching him he concentrated on the outside of camp half blood and shadow travelled away, very well aware of the warm body next to him.

Thanks for reading, your reviews are very much appreciated!


	3. Chapter 3

Disclaimer: Percy Jackson does not belong to me

Thanks for the review and please review again, thank you!

Nico stepped out of the shadow, pulling his friends with him. He was tired, sure, shadow traveling was draining but pure adrenaline fuelled him. The girl in his arms struggled in his grip and he had to let go of her, he was too physically weakened to keep her still. She scuttled backwards, backing up against Thalia's tree, her green eyes narrowing as she stared at each of them in turn.

"Bravo's" She muttered, gulping "Pernicious Bravo's" And with that she turned as if to run away but Percy leapt forward and gently grabbed her by the arm, stopping her in her tracks.

"Look, I have no idea what you're talking about but we're not gonna hurt you" He stated in a very sympathetic voice but the girl, Cassandra he remembered, tore her arm from his grasp.

"This is lunacy, am I just Expedient to one?" She questioned, beginning to look panicked. Nico had no idea what Cassandra was saying, the vocabulary she was using was very old fashioned and her voice was so soft and lulling he find it hard to concentrate on what she was saying.

"Um… Annabeth a little help here?" Percy whispered, his sea green eyes were wide. Annabeth stepped forward, raising her hands to show they mean no harm to the girl.

"Translated it means this situation is crazy, is she just a means to an end for you?" she said back, keeping her grey eyes locked on Cassandra's. When she saw that Nico and the others weren't planning on hurting her, Nico saw that she seemed to lower her guard down.

"No, no Cassandra it's not like that it's…" Percy stumbled, looking speechless. Cassandra's sea green eyes were focused on his, practically begging to know what was going on.

"Well… you see the thing is…" Annabeth started to say but Cassandra interrupted her, looking at Percy with great interest and even a little bit of trust.

"Your eyes" She murmured "They are the precise replica of mine – my mother constantly told me that they were the colour of trust and that should I ever meet one I should give my complete and utter trust to them" She whispered and Percy nodded jittery.

"Yes, yes… you can trust us" Percy exclaimed, looking incredibly relieved that the whole 'Pernicious Bravo's' situation was over. Nico watched as Percy slowly walked forward, obviously not wanting to scare her.

"Um… it's probably best if you come with us, Gaia may send more monsters" Percy said softly and Cassandra nodded, though her eyes portrayed incredible confusion.

"Before we take our leave, can you at least tell me that my sister is alright, I told her to run but… it was chaos out there I don't know what happened to her" Cassandra asked, her eyes sweeping over each of them. Nico's heart dropped. How were they supposed to tell her it was hundreds of years later and her sister was no doubt dead? Tricky? – Yeah, definitely.

Percy and Annabeth were looking directly at him, obviously thinking that because he was the son of the death god he should tell her. Nico didn't know how in hade's name they figured that one out – how could he possibly break that big of news to her.

"Cassandra…" Nico started to say, gulping back his emotions when she turned her sea green eyes on him, eyebrows furrowed together, "You're not in 1773 anymore… it's the year 2010… I'm sorry but your sister is gone" He stated, immediately regretting how blunt he sounded. He didn't mean for it to come out so… unfeeling, he didn't know how to deal with situations like this.

"Oh" Cassandra muttered, blinking away the tears Nico knew she was trying to hold back, "Um… does that mean I was once dead? How, I don't understand" She frowned, her voice hitching. Her long black hair was dusty from the mud and her plain dress was ripped and dirty.

"We will explain everything to you, I promise, but we have to get you to camp, it's just over there before the monsters pick up our scent – it's too dangerous out here" Nico said, a lot more softly than he thought. He wasn't usually this empathic, maybe it came with being a Hade's kid, or maybe it was losing his sister that changed him but it came as a surprise none the less. Her unusual, bright eyes locked on his for a long time, Nico didn't know exactly. He just continued to stare, and stare and stare, losing himself in those large green orbs. As soon as she broke eye contact and nodded shakily, refocusing her attention back on Percy and Annabeth Nico quietly cursed under his breath.

What in Hades had just happened? Instead of keeping on task and getting this girl to safety he had a staring competition with her? He felt his cheeks turn red as he stared at the ground, thinking over what had happened. Nothing like that had ever happened before, well – he'd looked at girls before, sure, but never had he felt… butterflies in his stomach or his heart beat faster, cliché but true.

Percy was staring at him weirdly, a look crossed between a knowing look and confusion. Nico dipped his head further, ignoring Percy's piercing gaze.

"This is the camp up here – it'll be like your new home, and most importantly, you'll be safe" Annabeth promised, already striding towards the camp's entrance. Percy tore his eyes away from Nico and smiled at Cassandra.

"Come on, once you'll safe we'll give you answers" And Cassandra nodded, following Percy. She started off rather unsteadily on her feet and Nico wondered if he'd have to catch her but she steadied herself and followed Percy determinedly, eyes roaming around the unfamiliar environment. Nico soon followed, watching out for any monsters that may have followed them to camp. When he was satisfied nothing was lurking in the distance he followed, racing through the camp's borders to catch up with friends.

He accidentally brushed up against Cassandra's arm, the touch sending shivers up his spine no matter how hard he tried to deny that feeling. Cassandra had her arms crossed across her chest as she limped forward. When their arms met she looked up at him, peeking through her long black hair. A small, uncertain smile made its way on her face and before Nico knew what he was doing he smiled back, secretly thrilled with the fact he made her smile.

Haha… next chapter… so much action guys, even some flashbacks – hope you'll stick me and please, please, please review – reviews are very encouraging.


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